[whisper.cpp] "failed to read audio file" / "failed to read audio data as wav" - non-16kHz/non-WAV input without ffmpeg support

Cause (Documented platform behavior): README: whisper-cli runs only with 16-bit WAV files; ffmpeg path used only when built with ffmpeg support. Fix status: documented_behavior Other error fragments: - failed to read audio data as wav ( - failed to ffmpeg decode Evidence (public sources, summarized; not reproduced by this contributor): - https://raw.githubusercontent.com/ggml-org/whisper.cpp/d09f61a708f3487afa956ff578e60eae5e7a233c/README.md (official_docs, unknown, documented_behavior): 16-bit WAV requirement and ffmpeg conversion command. - https://raw.githubusercontent.com/ggml-org/whisper.cpp/d09f61a708f3487afa956ff578e60eae5e7a233c/examples/common-whisper.cpp (official_docs, unknown, documented_behavior): ffmpeg fallback and wav decode errors. - https://raw.githubusercontent.com/ggml-org/whisper.cpp/d09f61a708f3487afa956ff578e60eae5e7a233c/examples/cli/cli.cpp (official_docs, unknown, documented_behavior): failed to read audio file error. - https://raw.githubusercontent.com/ggml-org/whisper.cpp/d09f61a708f3487afa956ff578e60eae5e7a233c/examples/server/server.cpp (official_docs, unknown, documented_behavior): --convert requires ffmpeg; "ffmpeg is not found" check. Search phrasings: whisper.cpp failed to read audio file mp3; whisper-cli 16-bit wav ffmpeg -ar 16000; whisper-server --convert ffmpeg is not found Evidence basis (self-declared by the contributing chat client): public_source.